Printing mechanism for adding and accounting machines



y 23, 1944- o. J. SUNDS'TRAND ETAL 2,349,769

PRINTING MECHANISM FOR ADDING AND ACCOUNTING MACHINES Filed Nov. 3, .1941

INVENTOR WALTER A. ANDERSON CAR 1/. JUIVDSTRAND BY WM ATTORNEY Patented May 23, 1944 ramrnwe MECHANISM ron. ADDING AND accorm'rmc. memes Oscar J. Sundstrand, West Hartford, and Walter A. Anderson, Bridgeport, Conn., assignors to Underwood Elliott Fisher Company, New York, N. Y., a corporation of Delaware Application November 3, 1941, Serial No. 417,642

3 Claims.

This invention relates to a double ribbon mechanism for computing machines and the like. Such mechanisms are used on business machines where it is desired to have two ribbon-inked copies produced simultaneously.

In prior constructions using two separate ribbons, it has been customary to support and feed the ribbons in one of the following two ways, generally.

1. The two ribbons are placed together and wound on one reel. The ribbons are then fed back and forth between the two reels similarly to the customary manner of feeding a single ribbon.

2. Two separate reels are used for each ribbon, each reel of one ribbon being geared or otherwise connected to the corresponding reel of the other ribbon for advancing the second ribbon.

The first of these two methods of supporting the ribbons has been found objectionable because the ribbons feed unevenly from one reel to the other, due to the varying diameters of the winding surfaces as the ribbons travel from one reel to the other. This method therefore requires additional mechanism to keep the ribbons taut. Furthermore, this first method does not permit the use of ribbons of different colors, for the differently colored ribbons will not retain their original colors when wound together on the same reel.

The second-mentioned method has been found objectionable because after a limited amount of use, the ribbons begin to vary in length, causing an undesirable slack to appear in one or the other. Therefore, with this method also it is necessary to provide the additional mechanism mentioned above to keep the ribbons taut.

It is accordingly an object of the present invention to provide a double ribbon mechanism that will feed. both ribbons evenly back and forth, and which will require a minimum of mechanical parts.

With this and incidental objects in view, the invention consists in certain novel features of construction and combinations of parts, the essential elements of which are set forth in appended claims, and a preferred embodiment of which is hereinafter described with reference to the drawing which accompanies and forms part of the specification.

In the drawing:

Figure 1 is a top plan view of the improved dual ribbon feeding mechanism showing the Figure 3 is a view similar to Figure 2, but illustrating the yielding action of one of the auxiliary ribbon feed pawis during the reversal of direction of feed when an auxiliary ribbon supply reel has become exhausted before the conventional ribbon supply reel is exhausted,

Figure 4 is a detail right side elevation of the ribbon feed mechanism, I

Figure 5 is a detail top plan view of an actuating cam therefor, and

Figure 6 is a detail top plan view of the conventional ribbon feed pawl.

The invention is illustrated in connection with a calculating machine of the type disclosed in U. 8. Patent No. 1,965,611, issued to Oscar J. Sundstrand on July 10, 1934, only a portion of the machine being shown.

Referring to Figures 1 and 4, the inner ribbon reels I are mounted on posts 2 joumaled on the machine frame 3. The reels are located in front of a platen 4 on opposite sides of type bars 5. Ratchet wheels 8, secured to posts 2, have openings to receive 9. depending stud such as 1 (Figure 4) secured in the lower flange of each reel, to drive the reels.

The ribbon feeding mechanism for the inner reels comprises a plate 8 having pawls 9 and in formed on its opposite ends. Plate 8 is mounted for lateral and longitudinal shifting movement on studs ll secured in a reciprocating member l5. Member i5 is slidably mounted upon studs l6 secured in the machine frame. A depending stud I! (Figure 4) on the right end of member I 5 extends into a cam slot I 8 (Figure 5) formed in a lever i9. Lever it corresponds to the lever 214 shown in U. S. Patent No. 1,965,611 and, as disclosed in that patent, oscillates during each cycle of the machine, imparting reciprocatory movement to member l5. Pawls 9 and III are arranged so that when one pawl is engaged with its corresponding ratchet wheel the other pawl will be disengaged from its wheel. The following construction is provided to effect this alternate engagement of the pawis. Adjacent each pawl 9 and ID are a pair of identical notches 20 (Figure 6), the inner notches of each pair being deeper than the outer notches. Springs 22, connected between plate 8 and member l5, normally with studs stud l4 the left pawl l9 engages the left ratchet wheel 6, and the shallow notch l4 of the righthand pair embraces the right-hand stud l4 to withhold the right pawl 9 from engaging its corresponding ratchet wheel 8. When the parts are in this position, the ribbon feeds from the right reel onto the left reel. Reversal of the direction of feed is effected by shifting plate 8 so that the deeper notch 29 of the right-hand pair embraces the right stud l4 and permits pawl 9 to engage the right ratchet 8, whereupon the shallow notch 29 of the left-hand pair embraces the left stud l4 removing and withholding the pawl Hi from engagement with the left wheel 3.

The following parts are provided to effect automatic reversal of the feed whenever the ribbon is completely unwound from one reel upon the other. Two oppositely disposed levers 23 and '24 are pivoted on studs It. A spring 25, connected between the forward ends of levers 23 and 24, tensions the levers clockwise and counterclock wise, respectively, about studs 16. Each lever carries upstanding ribbon guide posts 26 and 21 around which the ribbon feeds. Lever 23 has a lateral extension 28 arranged to cooperate with an upstanding stud 29 secured on pawl 9, and lever 24 has an identical lateral extension 30 arranged to cooperate with an upstanding stud 3| secured on pawl l0.

Assuming that the ribbon has completely unwound from the right reel upon the left reel (Figure 2), the continued effort of pawl Hi to feed the ribbon causes lever 23 to swing counterclockwise from the position shown in Figure 1 to the position shown in Figure 2, wherein extension 28 moves into the path of movement of stud 29. In this position extension 28 blocks the leftward movement of plate 8 during the ensuing leftward stroke of member I and causes studs M to shift to a position where the left notches 28 of each pair embrace the studs, the deeper notch of the right pair allowing pawl 9 to engage the right ratchet wheel 6, and the shallow notch 28 0f the left pair withholding pawl from engagement with the left ratchet wheel 6 as shown in Figure 3.

Reversal of the feed from left to right back to right to left is effected in the same manner, the continued effort of pawl 9, after the ribbon is completely unwound from the left reel, causing the ribbon to swing lever 24 clockwise and move extension 38 into the path of movement of stud 3|. This alternate reversal of feed occurs whenever either of the inner reels becomes exhausted.

Check dogs 32, pivoted on screws 33, are tensioned by springs 34 into engagement with ratchet wheels 6 to prevent backlash when the ratchet wheels 6 are engaged by their corresponding pawls 9 and Hi. It will be noted with reference to Figures l and 2, that the inner ends of the pawls 9 and ID are arranged to engage the check dogs and withdraw their corresponding dogs from 00- the wheels 38 and the reels 35. The auxiliary ribbon Extends aroundupstanding guide posts 31a secured in each of the brackets 31.

The feeding of the auxiliary ribbon i effected by two auxiliary feed pawls 42 and 43 attached by pin and slot connections 44 to plate 8. Springs 45, connected between pawls 42 and 43 and plate 3, normally urge the pawls toward each other and against upstanding studs 46 and 41 secured on plate 8. By this construction pawls 42 and 43 are shifted bodily into and out of engagement with their corresponding auxiliary ratchet wheels 33 concurrently with the shifting of pawls 9 and iii into and out of engagement with their corresponding ratchet wheels. A friction spring 39 (Figure 4), placed between bushing 40 and a nut and washer 4|, produces suflicient drag to. hold the auxiliary ribbon taut at all times.

Check dogs 48, pivoted on screws 49 and tensioned by springs 50 are arranged to be engaged with, or disengaged from, wheels 38 by the inner faces of pawls 42 and 43 in identically the same manner and for the same purpose as dogs 32.

Referring now to Figure 2 wherein the inner, right reel is shown completely unwound, and wherein extension 28 is shown in position to effect a change in the direction of feed from right to left (Figure 1) back to left to right, immediately upon the shifting of plate 8 pawl 43 withdraws from engagement with the left auxiliary ratchet wheel 38 concurrently with the withdrawal of pawl ill from engagement with the left inner ratchet wheel 6, and pawls 9 and 42 engage their corresponding ratchet wheels to start the feeding from left to right. It should be noted that the change of direction of feed occurs whenever an inner supply reel becomes exhausted, irrespective of whether either of the auxiliary reels are exhausted. This concurrent reversal maintains a uniform feeding of the ribbons.

Referring now to Figure 3, wherein the left auxiliary supply reel is shown completely unwound before the left inner supply reel is exhausted, it will be observed that no reversal of the direction of feed can take place until the inner reel is completely unwound and has caused extension 30 to be pulled into the path of movement of stud 3| to shift the pawls. This is accomplished by the lost motion connection 44, between pawl 42 and plate 8, permitting the continued feed of the inner ribbon while the auxiliary ribbon remains stationary, pawl 42 ceasing to have any operative effect on the right auxiliary ratchet wheel 38. Since the difference in the lengths of the two ribbons is never large, the number of printing impressions that are made while the auxiliary ribbon remains stationary are not sufficient to effect the clarity of the printing impression.

While the form of mechanism herein shown and described is admirably adapted to fulfill the objects primarily stated, it is to be understood that it is not intended to confine the invention to the one form of embodiment herein disclosed, for it is susceptible of embodiment in various forms all coming within the scope of the claims which follow.

What is claimed is:

1. In a machine of the class described, a dual ribbon mechanism including two ribbons, a separate pair of reels for each ribbon, a common actuator, separate feeding mechanisms for each pair of reels and operable by said common actuator to feed the ribbons from one reel of each pair to the other or vice versa, means under the control of one of the ribbons for changing the direction of feed of both ribbons upon the completion of feeding or said one ribbon in either direction and a yielding connection between the common actuator and the feeding mechanism of the other ribbon to suspend feeding operation of said other ribbon when that ribbon is completely fed prior to the completion of the feed of said one ribbon in either direction.

2. In a machine of the class described, a dual ribbonmeehanism comprising a main and an auxiliary ribbon, each extending in front of a printing point and between separate pairs of reel for each ribbon, ratchet wheels associated with the reels, an actuating member, pawls on the member engageable with two of the wheels for feeding the main ribbon from one of its reels to the other, and vice versa, auxiliary pawlson the member engageable with the other two wheels for feeding the auxiliary ribbon from one of its reels to the other, and vice versa, means under control of the primary ribbon for initiating a change in the direction of feed of bothribbons when the primary ribbon is completely wound in either direction. and yielding connections between the auxiliary pawls and the actuating member that render the feeding action of the auxiliary pawls ineffective in the event that said auxiliary ribbon becomes completely wound in either direction before the primary ribbon.

3. In a machine of the class described, a dual ribbon mechanism including two ribbons, each ribbon being secured to a pair of reels, 9. separate feeding pawl for one of the reels of each ribbon, means for actuating the feeding pawls simultaneously to advance the ribbon; in one direction, a separate pawl for eachof the remaining two reels, a connection between the last-mentioned feeding pawls and the actuating means to enable the actuating means to actuate the lastmentioned pawls, to advance the ribbons in the opposite direction, means to move the secondmentioned pawls to an ineffective position and simultaneously move the first-mentioned pawls into efiective position, and vice versa, and means controlled by one of the ribbons for operating the moving means whenever that ribbon is completely wound on either reel.

OSCAR J. SUNDSI'RAND.

WALTER A. ANDERSON. 

